Google shares go past the $US500 mark

Now the most valuable company in Silicon ValleyGoogle's stock price has surpassed $US500 ($A650) for the first time, marking another milestone in a rapid rise that has catapulted the internet search leader into the corporate elite.

Continuing a recent surge driven by Wall Street's high expectations for the company, Google's shares rose $US9.67 ($A12.57), or nearly two per cent, to $US504.72 ($A656.12) in morning trading on the Nasdaq Stock Market.

That left Google with a market value of about $US154 billion ($A200.19 billion) just eight years after former Stanford University graduate students Larry Page and Sergey Brin started the business in a Silicon Valley garage.

The Mountain View-based company is now Silicon Valley's most valuable business, eclipsing the likes of Intel, the world's largest computer chip maker, and Hewlett-Packard, a high-tech pioneer that also famously started in a garage 67 years ago.